Julia Wolfe, who founded the collective with Michael Gordon and David Lang, opened the show. Her 2005 oratorio “Steel Hammer,” ruminating on the mysteries surrounding the legend of John Henry, combines neo-medieval chant and stylized folk instrumentation: bristling banjo, shards of harmonica, sole taps on one musician’s shoes for an evocation of clogging.
This folk-medieval axis defined other performances, too. A rare, jewel-like solo set by Caroline Shaw found her looping and layering her voice into serene choral effects. Joan La Barbara’s “A Murmuration for Chibok,” performed by the Young People’s Chorus of New York City, set small, sinuous fragments of chant atop a cool vocal drone.
The Oliver Lake Crash Bang Trio’s raucous set pulled Mr. Lake’s sometimes smoky, sometimes squealing saxophone through pummeling thickets of drums. Mr. Gordon’s “No Anthem” was trembling waves for a small ensemble; Kaki King’s guitar pieces relaxed you into their strumming modesty before unexpectedly whipping into dizzying virtuosity.
I missed the final hours, including new work by Meredith Monk (though a bit of video ended up online), to travel over to Roulette for a program of Mr. Zorn’s “game pieces.” He had a piece — “Road Runner,” for solo accordion — performed at the very first Bang on a Can Marathon, and he and the collective have grown…